The present invention relates generally to gear drive mechanisms for wheeled vehicles in the nature of heavy duty apparatus used for construction, earth working, earth moving and the like.
More specifically, the invention relates to a double planetary drive assembly of large size and capacity for such vehicles, gears therein being of such size that a single ring gear, as sometimes heretofore used, can cause substantial difficulties in manufacture, primarily in shaping the ring gear teeth due to the very long shaper stroke required. Additionally, in large single ring gears, heat treating and the holding of required tolerances can also cause substantial difficulties.
Examples of final drive assemblies constituting prior art are shown for example in U.S. Pat. No. 3,452,612, entitled WHEEL DRIVE MECHANISM, and assigned to a common assignee herewith; and as set forth in my copending application for patent entitled WHEEL FINAL DRIVE ASSEMBLY FOR VEHICLES, application Ser. No. 879,304, filed Feb. 21, 1978, and also assigned to a common assignee herewith. In this patented structure, a single ring gear is shown, and the foregoing problems can exist with increases in size. In my copending application a composite or two-piece ring gear is broadly shown and contemplated, as are mounting means in the gear arrangement or system.
The present invention and application are directed to a composite, two component, or two piece, ring gear in a planetary system of the type in question. The present application discloses a construction which overcomes drawbacks and problems existing in prior known structures, and the structure further provides new and improved results as will appear hereinafter.
It is accordingly a primary object of the present invention to eliminate, in so far as possible, drawbacks existent in prior known and used apparatus, and further to provide a ring gear structure in a planetary gearing arrangement or system of a substantial advance in the art, and having meritorious improvements both from the standpoint of manufacture and operating capabilities and characteristics.